Perhaps some of the pins controlled by the programmer need pull-up (or -down) resistors to place them in a known and stable condition when the programmer is removed.pls explain pull-up or down, im a total newbie

A resistor that connects to either Vdd or Vss (which Atmel erroneously call Vcc and Vee IIRC).The purpose is to avoid floating inputs, as that could (and probably would) keep your program from running.

The pins that go to the programmer... Are any of them left unconnected when the programmer is removed?

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Regards,Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?Please remember...Engineering is based on numbers - not adjectives

so i checked connections all is good, theres definitely power going to to programmer. multimeter shows 4.95.could the programmer be faulty?

Where are you measuring at?

I looked at the wiring diagram you linked to earlier, and noticed that AVcc is connected to the positive pin of the programmer header. AVcc should be connected to Vcc, not as a power source for the programmer (it's the power source for port A and the AD converter) . It looks like it's being used as just another voltage source. I'm not really sure if that can wind up doing what you're observing, but I suspect it will throw off AD conversions if nothing else.

I'm still fighting a cold so maybe I'm not seeing something, but that wiring setup doesn't look right to me (at least not now).

I don't think it's pullups/pulldowns According to the data sheet it's just a SPI bus with some extra stuff to hold reset low. They don't show any pullup/pulldown resistors in the pinout.

Well, it won't run without the /Reset pulled high, and I wouldn't be surprised if that was missing, judging from it working with the interface connected (which make it very unlikely that the error should be anywhere else than in the interface part).

Logged

Regards,Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?Please remember...Engineering is based on numbers - not adjectives